Gas turbine engines generally include a turbine section downstream of a combustion section that is rotatable with a compressor section to rotate and operate the gas turbine engine to generate power, such as propulsive thrust. General gas turbine engine design criteria often include conflicting criteria that must be balanced or compromised, including increasing fuel efficiency, operational efficiency, and/or power output while maintaining or reducing weight, part count, and/or packaging (i.e. axial and/or radial dimensions of the engine).
Among turbine sections, define a turbine rotor assembly employing an outer diameter drum to connect rotors. Purge or cooling air is generally necessary to provide sealing and clearance control turbine rotors. Lack of methods and structures for control generally result in excessive air leakage around the relatively large outer diameters of the drums employed to connect rotors. The excessive leakages and lack of control generally result in efficiency losses that may significantly remove the performance and efficiency benefits of an outer drum turbine rotor assembly.
As such, there is a need for structures and methods to mitigate excessive air leakage and control clearances between outer diameter rotor and static structures of the turbine section.